SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f848be792d531f2e53b1ab1b5feee189ed494c44746753271aba71e96bff2442' 
  AND token = 'dfIVnhW1V61gLkDqZtvOX4qPoFyPYHWAxmHC1aZMYmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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