SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '640fe2305473d98a649f474d759f9a798c0d14c7550e41acdf7a2403385bad77' 
  AND token = 'UKV6Xo80xOUmsN5WRJaVqKbqYkmLxanjRQmuG8aGq8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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