SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cdfdaffc772c5d701820bead7cde2159801ef4e75a0bd58113b59b29456b8d' 
  AND token = 'XjPn3GRyDa6Vz5uoYZKulqrEQcthCokUUM9mvaMxTRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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