SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74445109ac6b913aa99f64cf91c62e797f764f88af0e43c3e8d794fb7d836cd7' 
  AND token = 'hRBRg6/wxHAROQMo55I5vD2NUgsBPb/2SLy7YKN9vtI=' 
  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"
    }
  }
}