SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5075c16bf3edf4016448c08ddebc522ead3e4c42549f4aa8a535360c460fc251' 
  AND token = 'cKzXpK3wx4GNX78O7rL92hssbRGzp190YKTs5y9NiXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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