SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4331c1a912038abe9fe57c4c3b46357c992fa2c63ffa5135fbc1dfe1d5746c47' 
  AND token = 'UWC6swHNdyK2EK/pAk64hXcbrG+PzEyusoFKqWk9Axg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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