SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88386633f651797328e9b17925ba4aad1bd55e6b73c4315fc440cfeb7f15afb6' 
  AND token = 'GmsQqk/3tFLgJF6CSCGCoHxBIal/JpfYd1o+0if8u4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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