SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5315c0912363104e11ad220c80bc31654576d503ba5d844d7dca76f0988f191' 
  AND token = 'EDnJBiaVXZpfIq1XSZy2fFcgzgjZ67swBatWfCBBNCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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