SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '352c4dba14fc60f2ba9e37a7820eca25a1d918086c8ab7693557be34b10a5ec5' 
  AND token = 'O91heGzOoeYX2QldFDy9Qpv57LznxKoeKJZc4NhBPQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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