SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba9d0a267a83bbb95ab080d12a38b00b2b61e643947de30df99681acd5f3917' 
  AND token = 'vLcK7FIXGz9WaBIyfx5HaqCz/sFXXAQp3ZHFvWwlNqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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