SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61d634ead7967f6723743a21c692aeaafdb3d8f8c24428a5e595d5b6e4221f85' 
  AND token = '2oeesF+/tE/9/blPHsU4Yy4hrHNE1unnPBAAVv0GKWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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