SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f07f002debccc56269c997010b2966eec4af9653183526607d2dfaf882820a4' 
  AND token = 'KcbDadVn/DLydtOKL1rSrXPxxHPOUo8Z8n9o4s7XCSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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