SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b30af2ee6ba463f803e257b6a057833dc958acd29d28d0b25de3219c27854b' 
  AND token = '6vSN1Qfh6cQbmUgZkJBxJ9RGPLr+vhfNZCSByBwyGrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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