SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55edffe2cfee9f0c9915f5e00310cdbb093073e88c26d3077a744d8330ff042b' 
  AND token = 'sMoWSEx7n5ooWmV9kiGAB0VViXHCfECTSDRUtxfIip4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}