SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78defeb06f9734ea8c9202032fff85a0f95a5d113269f603886669d563234536' 
  AND token = 'f5M3tTXMFsN067Aox+UI0dhAHkxFi50fRbEVbTFj1qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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