SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950921aa1e355f6c59071734de5d630c2d410d2bbf055e01c79a1de3982d7443' 
  AND token = 'iNRXi5iXuKgbnr9XIUWwsN+lSt1ZWmiw8DieJaxHgno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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