SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba423f1c9243143356201205578159772fc86a157594ba783e5b2bdb95681c5f' 
  AND token = 'zw5Imyqct5UpxBMIxhLBgorI8dm4bREl/WGNL+qdPCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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