SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '345c5fc919aa94f0ae04a8f3e8b33412c4894649850b52f6d916871d2cfa1881' 
  AND token = '5mT0Sft7dpzr4a/vS0a5L+12S/mlp0+sCYSGmL3L5AU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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