SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df4742b34f7474b3cb2b3fd87eaeb5ab5d9026b9ec74df26125f634696529db' 
  AND token = 'tkTpsmJnpNGs65HGfQGyPFejenajf82r4uDvgB6je98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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