SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8283ec8a9750c9b83bed48b6d4e80d45fc87b45a2f5b811a9b60c6e09d506331' 
  AND token = 'FojEflpmc/w8LZkbe/tdsyWiPxICo8h4IbGM/0HKfho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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