SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6659115a311be4db060dd4b2debcfdb5364988432425b2924d492edd166dbc67' 
  AND token = 'ySF2gKvtiavXFFow/HpDLzoW26oXrieXzqh/O5+nh84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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