SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '868019d71b20a254f0a5e4da34892c9dcae3fb53bd372748da520622eb29e813' 
  AND token = 'V2d0ikoTnvCU6NMKYYzKqkgd4jJpj04H2Av6h/wwtsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}