SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61036e8031cbea255e2bc7c7ce77992b0dad7bd33a640a02ed3c9ce3bb1b60dc' 
  AND token = 'xq6s20t3Rd2E3//u0xRbE+NvZnTDpo/qbVck9dRuZFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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