SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd720b437991942e3b80b870370217bc2be5957a77fd47a1b69467659a2163848' 
  AND token = 'UQp7XYw5qjPl/Ru8+siS42fLWu4Dasb9JdpGN7VM5hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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