SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fa825f42dc308a89edb4183b4c320e9af1188e3a06d92f4817133d76a88080b' 
  AND token = 'roGbK7ozRVipINDPfu8wJCvz6GO7KIvm6THgRmiPjWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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