SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26639bf1ff087a6d273cb824e3d73504a46dbaaf04dfe7ecaf137b162239e623' 
  AND token = 'tp3fGdgXw3P902teyKCKoukBM4z/Aa0H1HZMavGNcKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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