SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a72d68e716a1f7caa0ff104dd60c2dc3ee3cd6f338ef88e574bc74f479d51bf1' 
  AND token = 'sAtFGRAD/hkYlj6IvjAbS/piQMSRItPiV19y2yQecAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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