SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e03ff7bdc9a007d942b8a57a854564ba28e4806cbd0655d3ee6a53fcd747f56' 
  AND token = 'BhIECI2g8Qd8+wQ+1cd9FMPKoXqSSuH5PClkLt+VlMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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