SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c6944a4917c039891735346baf9b39d17dd13d424685fd4d585a25e10c304d3' 
  AND token = 'QZCC/LhTbP32/gwqY9JgVREfAAL6P8izQYZV/GjvHzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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