SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a22359153e14ac8a5b35902c2e1c738df89a5852fb2d624b28ac1bfdc1138ad' 
  AND token = 'A5UILvUXSkjlSGK54yrQOvSW5cRWigdWCTISfW307hY=' 
  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"
    }
  }
}