SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c8b359531bbe34c902f7edbabddf34db01f13f4cdcc3494b33de909105294af' 
  AND token = 'vDUwJPiXlrfin9fZQOcftGyFsl4jk69K5kshKR1r18w=' 
  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"
    }
  }
}