SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0235c166684f039fd3208105b21b360baca42e49bcfe098a2ca88a45bef3659' 
  AND token = 'D24+nwwb/eJ0sCNaLoawwIE+mwKns95rQ6662LIWAyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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