SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '527e3d1367bddcef7b01188ad272c49c131a7428eea0adcc4962a94bb5be8227' 
  AND token = 'ieheufLu+CspAKEgm5AS6zthYNxGlm8klk1gDbgRh2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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