SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ddac97531637ca8160baa82ab890e381721bb3f9632551822197bfcfaa1a9fd' 
  AND token = 'RxIpokUj+dO51iTXb+vVyLiabdx7pNtMSCgpMdJJt9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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