SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa75b6b0f62d19fc725a34b52166521883aacd0f094f42f57751dcb074a4a612' 
  AND token = 'im/ovhh8zpJqN3THWDd5Hn7qKQ9kvGsXmUAedDRghrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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