SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dd9ff7dc5322127fa05c951e2fd080ed6517258632fdb5ded676b2091322a0d' 
  AND token = 'z7sssrEa8NtN/LIFlucL999EzktkVAdgLgyMa+levK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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