SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d8a693f2806482d21d69ae175578bf8394b1fa17066c43135cde0982a15ab2a' 
  AND token = '+eslBlp7xaxhrRM4sdka0NKUkQCSgGb1DODw7GW81SQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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