SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '727230b9d1d3e8c8a8fb231d478ba4074ffd1a16d8d7d168bcc7597095a84a41' 
  AND token = 'R8879gfSbkv8QN1z/FfWkaiY1cWClWTtWzqu6Da3z9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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