SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5844aec6e65338dae14eaf22ad0b5781845696f74d0d3429baed3cbb3a799aa' 
  AND token = 'B0M7rDh8af/hTCUZKJvDLibzGmVXGSMHyJRl+8xQ6v0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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