SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51dc84581a56bc2c19d28660a1b0f7e2d594b53c5f24457db3b925a9665a9c3b' 
  AND token = 'OdgdWj70CEhuAagsR/3YqUZnI5imHDn9MQqVALJz2MI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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