SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70fee5ec97b90bc9d4bfffb8b8aeb304f5d18b0877a5041d91eecc93ec47349d' 
  AND token = 'X5mDsHHZbnNrArCuWt+dwQrZHzOiv4su3GRGUrciFvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}