SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fcaed2775729bf842b318b7d8271b8e2a9175bd5df44385e45389ad86f406ab' 
  AND token = '5EP2KxBvp84WSXBtzZOD95HjprscJZCOTBdmKCiwWKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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