SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f9bf07b8db15e4c39f2e0e822cbb9413656a24d0729cc459f1f849108af4543' 
  AND token = 'S3LyM366+PmNB1oX283KFIpuTEDjr4EzdartFvwM/TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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