SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409624be8a5dce2f16f816e14a7d37520bc9a727b4edd31b98cf393f13615c8f' 
  AND token = 'sfjKamnsq7kwqPqZPm8Q/+NpHa+hlT7vqOpVVHjDYFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}