SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1535965820d58212102520ceb4ba15e0cc75b985f70a982e5cdd307c19837d1' 
  AND token = 'BQSwwjG7hF7/Ve37k5L2AHdsKPGZCaVpPJaDsfoZ0ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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