SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5689f73f357ca0cea8bf1c42c06509cd3d172e70b489835e835ec765481cb813' 
  AND token = 'VzTwMnOuDT3DQEMtxZjK4RRLccBw1S0yW57rvt7MLSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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