SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd8423420be44c01a6d9fc30f4bafa562a74b92fc4e9daa0419fc7d829256486d' 
  AND token = 'kJcAWYKJuo+R+BajulODTEFjUm57rRQx9quBsmlnG/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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