SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deea37e3e53d779dd44620d935bae6150188eb5e221fe651e09748cf8b35d268' 
  AND token = 'v22FADFiRLVXUV9NW2WbSppkdTEnv+GcKjZfulz94zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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