SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e52b7f4fafff7088cac49f485ebd24066020bcdf7c72e4c634f0dfdcadc2dbe' 
  AND token = 'XCOUzC2Mczistd0hCYI7otr7dSjX4WiBFN7Sx+x3nVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}