SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc1e23d297f06005e36374f6dbd955c9165dc6001311966a3a8dab46a56e7272' 
  AND token = 'mj3HLi31v3MoOxRLbfjCAfgUhA8h8jW72epDOBQg6kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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