SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2da99a35bf21a98e5f8e0d211270067fd2621919305c4e868399ad791692cb25' 
  AND token = 'dGhB0yo2EmkNHyVkHzEDqXlc1CDBlrClmw9oovFePvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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