SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61b779e848cd3cd2371e4bb871aafd864ba35de1000754b22f07ffd78589be0c' 
  AND token = 'GWwAv+L/gmz3UG5Pl/88ebEuR52Srvk++PBoixH1uQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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