SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cf2087e96a608c796494b9fb5469751fdb13aee070e82fca3e5a8f51306f353' 
  AND token = 'MrKZyE2VG6tlbqaPYhiJCtr3v4jNt0lCPz+yhApVwE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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