SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '714b528066a355af29c9058ca82c512ec3a9a7e1b9abf23bd6bd47ed665c98dd' 
  AND token = 'Q6KAW0DDJrM/5swoqqnXnGIzr6r7GPXr2rb7DGGLpY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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