SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23c3cbd25ff99de2ab3969364c955592c9524e79a125d47d42d4c5a8207054fb' 
  AND token = 'RKJqVGJri6S9KA2GtdObISNng7hQgYQn6dv7Cgdhrdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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