SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41942e4cb7e0e897ad90f79082dd36876b7d2028c8b83073781cc46f6f402105' 
  AND token = 'FD4IRVeHJBKbgBHIRh7mHlaJ5PDcMKGwvQmWhh8ZQbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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