SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28fb126280a7cb85b967cf94ef58ede94d8bd9bdd0f2fe7eedbf083fc9163c38' 
  AND token = 'VxCw+98NfAI85HaU+/svj942jZzkotEqPyxyhT4wZe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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