SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc2b275280503713b2522f386149b678d635caef44a7825c68c202225cd69f64' 
  AND token = 'hP20peAhLVUvAsnvqJwSAFml3NQzJ+mg+fXkx04cjTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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