SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6855e1a22c08e6283ae87c4e30a97977305a4f8fadd675bdaf0b3093e3565941' 
  AND token = 'jpN8ue/O0Fam4MmQzJmwMYVyKMpuO9osnKzMwt7NEHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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