SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaa2812673edcfa5c5694a22e89c9cf8b5d3e37b60a947ee1f0b0932718269f7' 
  AND token = 'oIpODis8MHSYZVJ99AABVUF3Px3MbPGVtsBPQ/6hzlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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