SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a938d930952f42096913c46a40b0b52fbda4d690f6c32e0571b5ac32fef3ec97' 
  AND token = 'cjVHhWETK5IoUOZivh8pJ9c216mwKM47P7X0xCION/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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