SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b7b6a980071664bcf0efa01c53b93fe1401b686fbc00d465630e24f0cff2be72' 
  AND token = 'vqTRToVmOngjDVvQNX5cQCvd4Xm0o9PEKCKBX9o+FbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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