SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48acdabc8e4daad2aa63407821acd4ccd0267a5dadf63d0f3151dc1222a0f492' 
  AND token = 'ru2VQw30+pLQg95EFduRgM6f3m2BzAHabnXfog6xCrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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